Catalytic unit-independent phosphorylation and dephosphorylation of type II regulatory subunit of cyclic AMP-dependent protein kinase in rat liver plasma membranes

Rat liver plasma membranes contain a 55 kDa protein which proved to be identical with type II regulatory subunit (RII) of the cyclic AMP-dependent protein kinase (kinase A) by several criteria (gel electrophoretic behaviour, peptide map, position of the autophosphorylated site). Analysis of phosphopeptide maps revealed that the membrane-bound RII was phosphorylated by a kinase which is unrelated to the catalytic unit (C) of kinase A. Dephosphorylation of the membrane-bound RII by an endogenous phosphatase was stimulated by both cyclic AMP and fluoride. Addition of C did not stimulate dephosphorylation even in the presence of ADP; moreover, protein inhibitor of C did not modify the effects of cyclic AMP or fluoride. The effects of both cyclic AMP and fluoride were, however, inhibited by C. Results indicate that rat liver plasma membranes contain a phosphorylation-dephosphorylation system for which RII is a relatively specific substrate.

Ecdysterone selectively stimulates the expression of a 23000-Da heat-shock protein-beta-galactosidase hybrid gene in cultured Drosophila cells

To study the regulated expression of cloned heat-shock genes in homologous cells, hybrid Drosophila heat-shock-Escherichia coli beta-galactosidase genes were constructed. Segments of the ecdysterone-inducible 23,000-Da heat-shock protein (hsp23) gene and of two other hsp genes (hsp84 and 70), which are not hormone regulated, were functionally linked to the bacterial coding sequence, and the resulting hybrid genes were introduced into cultured, hormone-responsive Drosophila cells by transfection. All hybrid genes directed the synthesis of E. coli-specific beta-galactosidase in heat-treated cells. hsp23 hybrid gene expression was stimulated strongly by ecdysterone, while the activities of the other hybrid genes were not affected at all by the hormone. A hybrid gene with only 147 bp of hsp23 promoter sequence could not be activated by either heat or ecdysterone treatment. Thus, far upstream sequences contain signals required for the regulated expression of the hsp23 gene in Drosophila cells.

Binswanger's disease: progressive subcortical encephalopathy or multi-infarct dementia?

Since Binswanger's description of subcortical arteriosclerotic encephalopathy in 1894, numerous cases have been reported. Several authors doubt the validity of this malady, although the majority consider it to be a disease entity. We report seven cases with this type of pallor of myelin, only two of which are accompanied by a history of dementia. Among the seven cases, two had arteriosclerosis of penetrating arteries and arterioles in cerebral white matter. Electron microscopy showed splitting of myelin sheaths, probably the result of edema. In reviewing the blood supply of the cerebral white matter, we conclude that no pathological alterations of medullary branches of the cerebral arteries, the same vessels supplying the white matter, can give rise to such diffuse pallor of white matter and spare the arcuate fibres. This pallor can only be due to cerebral edema, most likely of hypoxic-ischemic, hypotensive, or acidotic origin. We also contend that arteriosclerosis can only cause dementia through multiple infarcts or lacunae, if it indeed leads to dementia.

Spongy degeneration of the CNS in infancy

We studied six cases of spongy degeneration of the CNS in infancy among Chinese. The main clinical features were cyclical vomiting and wailing, blindness, megalocephaly, convulsions, lethargy, and coma. Chief findings from light microscopic studies were spongiform change, moderate outfall of neurons, and marked astrocytosis, with formation of Alzheimer's cells type 2. Demyelination was only slight, if present. Electron microscopic studies revealed membrane-bound vacuoles, often containing membranous fragments or blisters and electron-dense granules.

Adult spinal muscular atrophy. A report of four cases

Four cases of spinal muscular atrophy (SMA) are reported, 3 with detailed autopsy findings. These are compared with 2 cases of typical amyotrophic lateral sclerosis (ALS) with neuropathological data. The 3 autopsy cases of SMA only showed decreased numbers of anterior horn cells in the spinal cord, with no change in the cortical pyramidal cells, including the Betz cells, and no degeneration of the pyramidal tracts, while the ALS cases showed loss both of lower and upper motor neurons and degeneration of the pyramidal tracts. In our opinion, the infantile, juvenile, adult, and late-life forms of SMA are really a single disease entity that occurs at varying ages and is separate from ALS. The term lower motor neuron disease would be preferable because the lesions are not limited to the spinal cord, but also occur in the brain stem.